Separator of fuel battery, method of joining separator, and fuel battery

ABSTRACT

In a separator member to be joined to an adjacent member adjacent thereto with an adhesive in a cell stacking direction, guide paths are provided to guide, in a specific direction, the adhesive applied to a joint surface of the separator member to be joined to the adjacent member. Thus, excessive adhesive is guided to the guide path, and associated disadvantages during joining can be eliminated.

TECHNICAL FIELD

The present invention relates to a separator of a fuel battery suitablefor being joined with an adhesive, a method of joining a separator, anda fuel battery.

BACKGROUND ART

In a fuel battery, a fuel battery cell serving as a single cell isconstituted by a membrane-electrode assembly (MEA) comprising anelectrolyte layer, such as a solid polymer membrane and diffusion layersof carbon cloth or carbon paper holding the electrolyte layertherebetween, and of separator members holding the membrane-electrodeassembly therebetween, and a plurality of such cells are arranged orstacked (modularized) to construct a fuel battery. In such a single fuelbattery cell, a hydrogen gas as an anode gas is supplied to a hydrogengas flow channel groove of the negative side separator, and air (oxygengas) as a cathode gas is supplied to an oxygen gas flow channel grooveof the positive side separator. The supplied hydrogen gas and oxygen gasare diffused to a negative side diffusion layer and a positive sidediffusion layer, respectively. The hydrogen gas which has reached thenegative side diffusion layer then contacts a catalyst layer appliedonto the solid polymer electrolyte membrane, and is dissociated intocharged protons and electrons. The dissociated protons pass through thesolid polymer membrane, move to a positive side, and react with theoxygen on the positive side to form water, thereby generatingelectricity. In general, a plurality of single cells having such a powergeneration mechanism is used and stacked via separators, such that theassembled fuel battery is constructed as a series-connected cell moduleor cell stack.

In order to bond the single cells of the fuel battery, a liquid adhesiveis used, and the single cells of the fuel battery are joined by thisadhesive. First, the liquid adhesive is applied onto a joint surface ofone separator member. The applied adhesive is solidified by thermalhardening after the joint surface of this separator member is coveredwith an adjacent member. In this manner, the separator can be joined tothe adjacent member by the adhesive. This liquid adhesive must beapplied onto the joint surface (at least the entire outer peripheraledge) of the separator member because if any places, even smalllocations, remain where the adhesive is not applied, the gas flowing inthe fuel battery may leak from the places where the adhesive is notapplied when the separator is joined to the adjacent member. To preventthis, it is therefore necessary to adequately apply the adhesive to theseparator member. That is, the adhesive has a function as a seal member.

The adhesive is preferably applied onto the joint surface (at least theentire outer peripheral edge) of the separator member as adequately aspossible, but application of too much adhesive may lead to otherproblems. That is, if the thickness of the adhesive applied onto theentire the joint surface of the separator member is not uniform andthere are places where the thickness of the applied liquid adhesivevaries, surface pressure distribution may vary when the separator memberis joined. For example, such a variation in the surface pressuredistribution weakens the adhesion force between the MEA and theseparator member by the adhesive, or increases the degree of electricloss (an increase in contact resistance) in the fuel battery. Moreover,between the separator member and the MEA, there is a possibility thatthe gas flow channels provided in the separator member may deform suchthat the gases will not flow along the designed flow channels.

A technique is known which, in view of such problems with the adhesiveapplication amount and the surface pressure distribution, crosses aleading end and a terminal end when applying the liquid adhesive. Atthis point, it is considered that the separator member is preferablyprovided with a wide portion in a part where the leading end is joinedto the terminal end.

Meanwhile, in the separator member onto which the adhesive is applied, aplace where the application amount of the adhesive is great is firstcompacted, and then other portions with the adhesive are compacted suchthat the separator member is bonded to the adjacent member, when theseparator member is bonded (sealed) with the adhesive to the adjacentmember (e.g., the electrolyte membrane, the separator, a resin frame,etc.) opposite to the separator member in a cell stacking direction.Especially at a cross portion of the adhesive, the adhesive is appliedso as to be superposed in two or more layers, which tends to create abulky state.

At this point during assembly, because the surface pressure in such abulky cross portion becomes higher than in other portions, the compactedadhesive spreads over the periphery of the cross portion. Especially,depending on the condition when the separator member is joined to theadjacent member with the adhesive, the direction and amount in which thecompacted adhesive spreads out can vary.

A conventional separator member is provided with a wide portion atportions where the leading end crosses the terminal end. However, whenthe compacted adhesive disproportionately spreads within the space ofthe wide portion depending on the condition during the joining, theadhesive in some cases runs over from the wide portion in an arbitrarydirection.

Such overflowing adhesive might, for example, enter and block the gasflow channels or a cooling fluid flow channel of the separator, orhamper the function of the MEA. Further, when the adhesive runs overinto a manifold for the gas flow channels and the cooling fluid flowchannel formed in the separator member, the adhesive hampers the flow ofthe gases or a cooling fluid. Moreover, when there is a possibility thatthe adhesive may overflow into the manifold, it may be necessary toinclude in the manufacturing process an additional process for removingthe run-over adhesive. In addition, there is a possibility thatdeviation in the wide portion will lead to variations in the applicationamount (surface pressure) and impair the sealing function.

The present invention was made in view the above problems, and providesa separator of a fuel battery having a more suitable bonded structureand a fuel battery using this separator.

DISCLOSURE OF THE INVENTION

The present invention provides a separator of a fuel battery including aseparator member to be joined to an adjacent member adjacent theretowith an adhesive in a cell stacking direction, wherein a joint surfaceof the separator member to be joined to the adjacent member is providedwith guide paths to guide the applied adhesive in a specific direction.

Thus, when the separator of the fuel battery including the separatormember is joined to the adjacent member with the adhesive in the cellstacking direction, the adhesive applied when the separator member isjoined to the adjacent member is guided in a specific direction alongthe joint surface of the separator member to be joined to the adjacentmember.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a fuel battery module according to anembodiment of the present invention;

FIG. 2 is a plan view of a fuel battery separator according to theembodiment of the present invention;

FIG. 3 is a sectional view of the fuel battery separator according tothe embodiment of the present invention;

FIG. 4 is a sectional view of the fuel battery separator according tothe embodiment of the present invention;

FIG. 5 is a sectional view of the fuel battery separator according tothe embodiment of the present invention;

FIG. 6 is a sectional view of the fuel battery separator according tothe embodiment of the present invention;

FIG. 7 is an explanatory diagram showing how an adhesive is applied tothe fuel battery separator according to the embodiment of the presentinvention;

FIG. 8 is an explanatory diagram showing an adhesive application processaccording to the embodiment of the present invention; and

FIG. 9 is an explanatory diagram showing the adhesive applicationprocess according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to the drawings. The present embodiment is one example ofhow the present invention can be implemented, and the present inventionis not limited to this example embodiment.

Fuel Battery and Separator of Fuel Battery

A sectional view of a stack structure of a fuel battery 100 according tothe present embodiment is shown in FIG. 1. The fuel battery 100 has astacked structure in which a plurality of single fuel battery cells 40are stacked (modularized). Here, each single fuel battery cell 40 has astructure in which an MEA 30 is held between a first separator member 10and a second separator member 20. The first separator member 10 and thesecond separator member 20 correspond to adjacent members of each other.

A single fuel battery cell 40 is constructed by joining the MEA 30between the first separator member 10 and the second separator member 20with a thermosetting adhesive 22. The fuel battery stack structure 100is produced so that the fuel battery cells 40 thus formed are furtherjoined with the adhesive 22 and the fuel battery cells 40 are physicallyfirmly bonded to form a cell module. The cell modules are furtherstacked to form a cell stack. Terminals, insulators, and end plates arearranged at both ends of the cell stack in a cell stacking direction,and the cell stack is fastened in the cell stacking direction, and thena tension plate extending in the cell stacking direction is fixed bybolts and nuts outside the cell stack, thereby constructing a fuelbattery stack. In this manner, the fuel battery according to the presentembodiment can be manufactured.

A plan view of one second separator member 20 to be stacked in the fuelbattery 100 is shown in FIG. 2. The second separator member 20 hasconvex walls 12 on its outer peripheral portions and on the outerperipheral portion of a manifold 80. Portions surrounded by the convexwalls 12 are adhesive application grooves 14. Further, both the topsurfaces of the convex walls 12 and the adhesive application grooves 14surrounded by the convex walls 12 constitute a joint surface.

For the first separator member 10 and the second separator member 20,carbon, a metal, a resin, a conductive resin or the like can beemployed. For example, it is possible to employ a combination of metalseparators for the first separator member 10 and the second separatormember 20, or a combination of carbon separators (molded articlescomprising carbon and a resin for binding the carbon) for the firstseparator member 10 and the second separator member 20. In FIG. 1, thecarbon separators are used for both the first separator member 10 andthe second separator member 20.

Furthermore, the adjacent member can be at least one of the separator,an electrolyte membrane, the membrane-electrode assembly and a resinframe.

Moreover, the MEA 30 is formed in such a manner that a solid polymermembrane is held between diffusion layers at both poles. Here, afluorine-based resin or the like may be used for the solid polymermembrane, and a general diffusion layer forming material such as carbonpaper or carbon cloth may be used for the diffusion layers.

The first separator member 10 and the second separator member 20 have aplurality of gas flow channel grooves 32 on MEA contact surface sidesfor holding the MEA 30 at positions for holding the MEA 30 therebetween.The gas flow channel groove 32 is a concave groove, and a fuel gas andan oxidized gas for the fuel battery are supplied to the MEA 30 throughthe gas flow channel grooves. The gas flow channel 32 may be aserpentine flow channel extending from an entrance to an exit so as toturn back one or more times, or a straight flow channel extendingstraight from the entrance to the exit. As shown in FIG. 1, the fuelbattery stack structure 100 has the manifold 80 connecting with the gasflow channels 32 so as to penetrate the separators for the passage orthe gases of a cooling fluid.

A characteristic point of the present embodiment is that, as shown inFIG. 2, the first separator member 10 and the second separator member 20have the adhesive application grooves 14 to which the adhesive isapplied, and the convex walls 12 defining the adhesive applicationgrooves 14.

The adhesive application groove 14 is a concave groove for which theconvex walls 12 protruding from the surface of the second separator 20serve as dams of lateral surface walls and the surface of the secondseparator 20 serves as a bottom surface. This structure makes itpossible for the adhesive application groove 14 to have a function ofretaining the adhesive. The adhesive application grooves 14 are providedin both the first separator member 10 and the second separator member20, and the first separator member 10 and the second separator member 20are arranged so that the adhesive application grooves 14 face each otherafter the adhesive 22 is applied thereto. Then, the first separatormember 10 is joined to the second separator member 20 with the adhesive22 retained in the adhesive application grooves 14, and the fuel batterycells 40 are formed into a stacked module. Hereinafter, the secondseparator member 20 will be explained by way of example.

Furthermore, the adhesive application groove 14 is divided into an outerperipheral adhesive application groove 19 provided in the outerperipheral surface of the joint surface of the second separator member20, and an inner peripheral adhesive application groove 18 located inplaces other than on the periphery thereof and provided on the peripheryof the manifold 80 and the like of the second separator member 20.

The convex walls 12 defining the adhesive application grooves 14 aredams protruding on the surface of the second separator member 20. Theconvex walls 12 are provided so as to enclose the outermost peripheralportion of the second separator member 20 and so as to enclose theperiphery of the manifold 80. The convex walls 12 are provided in bothseparators to be joined together. When a cell module is formed, theconvex walls 12 provided on the joint surfaces of both separatorsdirectly contact each other so that the separators are stacked, as shownin FIG. 1.

The convex wall 12 has a plurality of guide paths 16. The guide paths 16penetrate from the outside of the second separator 20 into the adhesiveapplication grooves 14. Openings are provided along the outer peripheryof the convex wall 12 in order that the guide paths 16 will formopenings. That is, because the concave adhesive application groove 14 isdefined by the bottom surface of the second separator 20 and the convexwalls 12, the convex walls 12 are formed with openings which serve asthe guide paths 16.

The guide paths 16 (16 a, 16 b, 16 c and 16 d) are provided extendingtowards adhesive cross points 15 (15 a, 15 b, 15 c and 15 d) in theadhesive application grooves 14. Further, in the present embodiment, aguide path 16 e is also provided in the ordinary adhesive applicationgroove 14 where there is no cross point. It is to be noted that theguide path 16 e is not necessarily required and can be omitted.Hereinafter, a place where the guide path 16 is provided and a placewhere the guide path 16 is not provided are described comparingsectional views thereof. The sectional configuration of the secondseparator 20 is disclosed in FIGS. 3 to 6.

FIG. 3 shows a sectional view through the second separator 20 havingadhesive application grooves 14 including a section of the manifold 80in an A-A′ surface having no guide path. In the sectional view shownhere in FIG. 3, from the outside of the separator to an MEA holdingportion (from left to right in the drawing), there are formed the convexwall 12, the outer peripheral adhesive application groove 19, the convexwall 12, the manifold 80, the convex wall 12, an inner peripheraladhesive application groove 18 a and the convex wall 12.

In FIG. 4, there is illustrated a sectional view through the outerperipheral portion of the second separator 20 along a B-B′ surfacethereof. In the configuration shown in FIG. 4, there are formed, fromthe outside of the separator to the MEA holding portion (from left toright in the drawing), the convex wall 12, the guide path 16 a and theconvex wall 12. The guide path 16 a is formed by gaps in the convex wall12. The bottom surface of the guide path 16 a has such a structure as tocontinue from the bottom surface of the adhesive application groove 14.Having such a continuous structure, the guide path 16 a is a concavegroove, and is defined by the convex walls 12 serving as both lateralsurfaces and by the surface of the second separator 20 serving as abottom surface.

In FIG. 5, there is illustrated a sectional structure through the secondseparator 20 including the section of the manifold 80 in an C-C′ surfacehaving the guide path. In the configuration shown in FIG. 5, the guidepath 16 e, the outer peripheral adhesive application groove 19, theconvex wall 12, the manifold 80, the convex wall 12, the innerperipheral adhesive application groove 18 a, and the convex wall 12 areformed, in that order, from the outside of the second separator to theholding portion of the MEA 30 (from left to right in the drawing).

In FIG. 6, there is illustrated a sectional view through the secondseparator 20 along a D-D′ surface. In the sectional view shown here,from the outside of the separator to the MEA holding portion (from leftto right in the drawing), there are formed the guide path 16 c, theouter peripheral adhesive application groove 19, the inner peripheraladhesive application groove 18 a, and the convex wall 12. Here, theguide path 16 c is provided with a concave depression 17. This concavedepression 17 is provided in the bottom surface of the guide path 16 c.This concave depression 17 serves as an adhesive reservoir to retain theguided adhesive. It is to be noted that the place to provide the concavedepression 17 is not limited to the bottom surface of the guide path 16,and the concave depression 17 may be provided at an arbitrary place inthe bottom surface of the adhesive application groove 14. Moreover, theadhesive reservoir is not limited to the concave depression 17, and mayhave any structure as long as it can store the adhesive. For example,various forms, such as a conical depression or atriangular-pyramid-shaped depression, may be employed.

The convex walls 12 are preferably provided on the periphery of themanifold 80 and in the outer peripheral portion of the second separator20. The convex wall 12 provided on the periphery of the manifold 80 canprevent the adhesive from entering the manifold 80. The convex walls 12provided in the outer peripheral portion of the second separator 20 canprevent the adhesive from overflowing from arbitrary places in the outerperipheral portion of the second separator 20. That is, because theseparator in the present embodiment has a structure in which theadhesive is guided by the guide paths 16 to flow through specificegresses, it is possible to prevent a disadvantage that the adhesiveoverflows at arbitrary places.

The convex walls 12 provided on the periphery of the manifold 80 and inthe outer peripheral portion of the second separator 20 can simplify amodularization jig structure used in a process of joining the MEA andthe first separator 10 to assemble a unit cell. For example, owing tothe presence of the convex walls 12, a flat plate jig which enablesaccurate modularization can be used as a modularization jig. Therefore,effects dependent on the modularization jig in a modularization process(e.g., effects on the variation of the thickness of the single cells)can be eliminated.

It is to be noted that the guide path is defined as a concave groove inwhich the convex walls 12 serve as lateral side walls (the guide path16) in the present embodiment, but it is not limited to the use of theconvex walls 12. Any configuration is possible as long as the guide pathis provided so that the adhesive can be guided to a particular place.

Method of Joining Separator

Next, application of the adhesive 22 to the second separator 20 alongthe adhesive application grooves 14 will be described. FIG. 7 shows howthe liquid adhesive is applied in an arrow direction in the secondseparator along the adhesive application grooves 14. Here, a dispenseris used for application.

FIG. 8 shows application of the adhesive 22 using the dispenser. Thedispenser (not shown) comprises a dispenser nozzle 24. The adhesiveapplication groove 14 as an application target is disposed immediatelyunder an adhesive injection outlet of the dispenser nozzle 24. Togetherwith the movement of the dispenser nozzle 24 over the adhesiveapplication groove 14, the adhesive 22 is injected from the tip of thedispenser nozzle 24. Thus, the adhesive 22 is applied to the adhesiveapplication groove 14.

A start point of the dispenser nozzle 24 is set at a point P. Thedispenser moves along the outer peripheral adhesive application groove19 from the point P (see arrows), thereby applying the adhesive 22.First, the adhesive 22 is applied so as to pass the cross point 15 a andreach a point at a corner portion Q. Then, the corner portion Q ispassed to reach the cross point 15 b, and a corner portion R point isreached from the cross point 15 b. Finally, after passing the cornerportion R point, a point S, which is the end point of the adhesiveapplication groove 14, is reached. In this manner, the adhesive 22 isapplied to the outer peripheral adhesive application groove 19 enclosingthe outer peripheral portion of the separator 20.

Next, after the adhesive 22 has been applied to the outer peripheraladhesive application groove 19, the adhesive 22 is applied to the innerperipheral adhesive application grooves 18 (18 a, 18 b). A method ofapplication to the inner peripheral adhesive application groove 18 awill be described. The adhesive 22 is applied to the inner peripheraladhesive application groove 18 a by the dispenser from the cross point15 b to the cross point 15 a. Here, the application is started from thecross point 15 b in such a manner as to overlap the adhesive 22 appliedto the cross point 15 b so that there is no part where the adhesive 22is not applied in the condition in which the adhesive 22 is crushed andspread out when bonded to the adjacent member. The corner portion ispassed to reach the cross point 15 a. At the cross point 15 a, theadhesive 22 is also applied up to the position where it overlaps thecross point 15 a so that no portion where the adhesive 22 is not appliedremains.

Next, a method of applying the adhesive 22 to the inner peripheraladhesive application groove 18 b will be described. This is similar tothe method of applying the adhesive 22 to the inner peripheral adhesiveapplication groove 18 a. That is, the dispenser is used to apply theadhesive 22 to the inner peripheral adhesive application groove 18 bfrom the cross point 15 c to the cross point 15 d. Here, the applicationof the adhesive 22 is started from the cross point 15 c in such a manneras to overlap the adhesive 22 already applied to the cross point 15 c sothat there remains no part where the adhesive 22 is not applied. Thecorner portion is passed to reach the cross point 15 d. At the crosspoint 15 d, the adhesive 22 is also applied up to the position where itoverlaps the cross point 15 d so that no portion where the adhesive 22is not applied remains.

The liquid adhesive 22 is applied along the adhesive application groove14. Although a dispenser is generally used for this application, thepresent invention is not so limited, and other application methods, suchas screen printing or the like, can also be employed. Moreover, theadhesive application groove 14 has the cross points 15. At the crosspoints 15, the liquid adhesive 22 is applied in a superposed state.

When such an application process is carried out, only one layer of theadhesive 22 is applied in the adhesive application groove 14 except forthe cross points 15, whereas the adhesive 22 is applied in two layers atthe cross points 15 (15 a, 15 b, 15 c and 15 d) (FIG. 9). In this state,the separator member is joined to the adjacent member via an adhesiveapplied surface.

In this separator member joining method, the amount of the adhesive 22applied at the cross points 15 (15 a, 15 b, 15 c and 15 d), where theadhesive 22 is double-layered, is greater than in the rest of theadhesive application groove 14 without the cross points 15. In somecases, the amount of the adhesive 22 is excessive. When joining theseparator member, a buffer portion is required to remove the excessiveadhesive 22. Without the buffer portion, the adhesive 22 may cross overthe convex wall 12 to run over to the surface on the convex wall 12.Further, the adhesive 22 may reach the inner surface of the manifold 80.

In the second separator member 20 of the present embodiment, the guidepaths 16 (16 a, 16 b, 16 c and 16 d) of the convex walls 12 are providedextending toward the cross points 15 (15 a, 15 b, 15 c and 15 d), sothat the excessive adhesive 22 at the cross points 15 is guided to theguide paths 16 and expelled when the separator member is joined. At thispoint, it is also preferable that by reducing pressure on the peripheryof a joint member of the separator member and the adjacent member,particularly in the vicinity of the openings of the guide paths 16, theexcessive adhesive 22 is actively drawn into the guide paths 16.

As described above, the guide paths 16 of the convex walls 12 areprovided to connect to the cross points 15, such that the excessiveadhesive 22 is guided to the guide paths 16, and the amount of theadhesive 22 can be restrained from becoming excessive even at the crosspoints 15, thereby making it possible to secure a proper applicationamount of the adhesive 22.

In the present embodiment, the applied adhesive 22 can be activelyguided and handled. Moreover, because the guide path 16 connects theadhesive application groove 14 with the outside of separator member, theadhesive 22 can be guided from the guide path 16 to outside of theseparator member, so that the adhesive 22 may be expelled from theopenings to outside the separator member. In such a case, it may also bepreferable that pressure in the vicinity of the openings be reduced toactively discharge the excessive adhesive 22 from the openings. Thus,the excessive adhesive 22 can be guided to a desired location. Moreover,because since the adhesive 22 is discharged from particular placescorresponding to the guide paths 16, the adhesive 22 need only bedeburred in the outer surface of the separator member corresponding tothe particular points. Therefore, a deburring process can be simplified.

The guidance of the adhesive 22 by the convex walls 12 and the guidepaths 16 facilitates the removal of the excessively applied adhesive 22.Thus, it is possible to prevent the applied adhesive 22 from overflowingfrom application parts when joining the separator member. It is alsopossible to prevent disadvantages that the adhesive 22 overflowing fromthe application parts reaching the MEA to disturb the power generationof the fuel battery or the adhesive 22 overflowing into the manifold 80.In addition, it is not necessary to carry out a complicated deburringprocess within the manifold 80.

Furthermore, when the separator member is a metal separator, ananticorrosive layer is generally provided on the inner surface of themanifold. Therefore, there is conventionally a danger of releasing theanticorrosive layer if the adhesive adhering onto the inner surface ofthe manifold is deburred, such a disadvantage can also be preventedaccording to the present embodiment.

Especially, when the concave depression 17 is provided in the bottomsurface of the guide paths 16 c, the depression 17 can store theadhesive therein. Thus, the excessive adhesive 22 can be stored in thedepression 17 when joining the separator member. In this manner, it ispossible to prevent the adhesive 22 from overflowing through the guidepaths 16 c to outside the separator member, thereby eliminating any needfor a deburring process in such locations.

When the guide path 16 e is provided in the separator member, thelocation of the guide path 16 e is preferably set in consideration ofthe possibility of overflowing of the adhesive 22. For example, it isconceivable that the separator member may cause distortion and that thedistorted part may bulge so that the adhesive 22 overflows during thejoining process. In consideration of this possibility, it is desirableto dispose the guide paths 16 in parts where distortion is more easilycaused. The distortion is easily caused particularly when the separatormember is a metal separator, and the provision of the guide path 16 istherefore effective in the parts where the distortion is easily caused.

It is to be noted that the place where the adhesive 22 is guided may beeither or both of the guide path 16 and the concave depression 17.Whether either or both of these features are provided in the separatormember may be decided in consideration of balances such as facility ofmanufacture etc.

INDUSTRIAL APPLICABILITY

The present invention can generally be applied to a separator of a fuelbattery of a solid polymer type, phosphoric acid type, molten carbonatetype, solid oxide type or the like.

The invention claimed is:
 1. A separator of a fuel battery comprising aseparator member and an adjacent member adjacent to the separator memberin a cell stacking direction and joined to the separator member with anadhesive, wherein: application paths of the adhesive are provided on ajoint surface of at least one of the separator member and the adjacentmember, the application paths cross each other, and each applicationpath comprises an application groove defined by convex walls provided onthe joint surface as lateral surface walls, guide paths of the adhesiveare provided on the convex wall by openings formed in parts of theconvex wall, wherein at least one of the guide paths connects a crosspoint of the application paths to an outside of the separator with astraight line, the at least one of the guide paths comprises a concavegroove defined by convex walls as lateral surface walls, the at leastone of the guide paths is configured to guide redundant adhesive to theoutside of the separator, and the at least one of the guide paths isflat and continues from the application paths, and a depression isformed on a bottom surface of the concave groove as an adhesivereservoir depressed with respect to the bottom surface of theapplication groove.
 2. The separator of the fuel battery according toclaim 1, wherein the joint surface is the joint surface of the separatormember, and the at least one of the guide paths comprises the concavegroove defined by the convex walls protruding from the surface of theseparator member as lateral surface walls and by the surface of theseparator member as a bottom surface.
 3. The separator of the fuelbattery according to claim 2, wherein the convex wall is provided on atleast one of the periphery of a manifold and the outer periphery of theseparator.
 4. The separator of the fuel battery according to claim 1,wherein the adhesive reservoir is a concave depression.
 5. The separatorof the fuel battery according to claim 1, wherein the adhesive is athermosetting adhesive.
 6. The separator of the fuel battery accordingto claim 1, wherein the separator member and the adjacent member aremetal separators.
 7. A fuel battery comprising a separator of a fuelbattery according to claim
 1. 8. A method of joining a separator of afuel battery comprising a separator member and an adjacent memberadjacent to the separator member in a cell stacking direction and joinedto the separator member with an adhesive, the method comprising:providing application paths of the adhesive on a joint surface of atleast one of the separator member and the adjacent member, providingguide paths of the adhesive connecting cross points of the applicationpaths to an outside of the separator, at least one of the guide pathscomprising a concave groove and a depression formed on a bottom surfaceof the concave groove, the at least one of the guide paths being flatand continuing from the application paths, applying the adhesive only onthe application paths among the application paths and the guide paths,the adhesive being applied on the cross points of the application pathsin a superposed manner, joining the separator member and the adjacentmember via the surface on which the adhesive is applied, after theapplication of the adhesive to the application path, and guidingredundant adhesive to an outside of the separator and the adjacentmember via the guide paths when the separator member and the adjacentmember are joined.
 9. The joining method according to claim 8, whereinthe concave groove is defined by convex walls protruding from thesurface of the separator member as lateral surface walls and by thesurface of the separator member as a bottom surface.
 10. The joiningmethod according to claim 9, wherein the guide paths are produced byopenings formed in parts of the convex walls.
 11. The joining methodaccording to claim 9, wherein the convex wall is provided on at leastone of the periphery of a manifold and the outer periphery of theseparator member.
 12. The joining method according to claim 8, whereinthe adhesive is guided to an adhesive reservoir provided on a jointsurface of at least one of the separator member and the adjacent member.13. The joining method according to claim 12, wherein the adhesivereservoir is the concave depression.
 14. The joining method according toclaim 8, wherein the adhesive is a thermosetting adhesive.
 15. Thejoining method according to claim 8, wherein the separator member andthe adjacent member are metal separators.